In addition to supporting implicit feedbacks of channel status information such as an RI (rank indication), a CQI (channel quality indicator), and a PMI (precoding matrix indication) of an LTE system, an LTE-A (Long Term Evolution-Advanced) system may further support a direct feedback of channel status information such as a channel matrix feedback or a channel covariance matrix feedback, which are collectively referred to as a CSI (channel state information) feedback.
In the existing LTE R12 (LTE release 12), only a PUCCH resource in a PUCCH (physical uplink control channel) format 2 is used for CSI transmission. A maximum quantity of bits that are supported by the format is 11. In addition, a 32-CA (carrier aggregation) technology is introduced to an LTE R13 (LTE release 13) system. As stipulated in the LTE R10 (LTE release 10) standard, a parameter corresponding to CSI of each downlink carrier is independently configured, and parameters such as a PUCCH resource used to transmit CSI of each downlink carrier and a report period are also independently configured. In a 32-carrier aggregation scenario, CSI corresponding to each carrier needs to be reported by using a separate PUCCH resource. Therefore, overheads of PUCCH resources occupied for CSI reporting are relatively large. In other words, a throughput of an uplink system is reduced.